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Updated: May 2, 2026

Glass-Based Devices to Generate Drops and Emulsions
Published on: April 5, 2022
Spontaneous Coulomb fissions of drops on lubricated surfaces
Marcus Lin1,2, Peng Zhang1, Aaron D Ratschow3
1Physical Science and Engineering Division, King Abdullah University of Science and Technology, Thuwal 23955-6900, Saudi Arabia.
Abstract:
Charged water drops are more widespread than commonly acknowledged. For example, raindrops typically carry charges of order [Formula: see text] pC, while routine pipetting in the laboratory produces drops with [Formula: see text] pC. Here, we show that such modest charging can spontaneously generate periodic Coulomb fissions for evaporating water drops on lubricated surfaces, with more than 60 successive cycles observed over 30 min. Interestingly, the underlying instability can be quantitatively predicted by two fissility thresholds: one marking the onset of drop elongation and another triggering fission. Each fission culminates with a fine liquid jet that disintegrates into 40 to 50 microdroplets, expelled within microseconds. The phenomenon spans an extraordinary range of length scales (from millimeters to microns) and time scales (hours to microseconds), with broad potential applications ranging from nanoscale fabrication to electrospray ionization.
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